A heavy voter turnout is expected Tuesday in the next phase of the U.S. presidential election campaign. Nominating primaries are being held in Maryland, Virginia and Washington, D.C., and VOA National correspondent Jim Malone has a report.

Lengthy lines were reported at several polling stations and interest was running high in the Democratic presidential nomination race between Senators Hillary Clinton and Barack Obama.

Two voters in Virginia, who cast ballots in the Democratic primary, expressed their opinions on the race.

"I voted for Hillary Clinton. I really don't like Obama. I think he is really naïve on foreign policy," said one man.

"Obama. He is the better candidate," said another voter.

Obama was looking to build momentum after a series of recent victories as he rallied supporters at the University of Maryland on the eve of the primaries.

"We cannot wait to stop global warming," he said. "We cannot wait to bring this war in Iraq to a close. We cannot wait to fix this country."

Public opinion polls give Obama the edge in Maryland, Virginia and the District of Columbia, thanks in part to strong support from African-American voters.

Clinton also campaigned in Maryland and promised to battle Obama for votes in all three races. But Clinton made clear that she is looking ahead to the March 4 primaries in Texas and Ohio, states where she has a lead.

"I am absolutely looking to Ohio and Texas because we know that those are states that represent the broad electorate in this country," she said. "They represent the kind of voters that are going to have to be convinced and won over in the general election."

Clinton and Obama are roughly tied in the delegate count. The Associated Press estimates both candidates have more than 1,000 delegates each. It takes 2,025 delegates to win the Democratic nomination.

In the Republican presidential race, Senator John McCain of Arizona is looking to solidify his hold on his party's nomination with victories in Maryland, Virginia and the District of Columbia.

McCain has a huge lead in the delegate count over his main remaining challenger, former Arkansas governor Mike Huckabee.

Huckabee beat McCain in two of three Republican contests over the weekend and hopes to surprise McCain in Virginia with the support of conservative Christian voters.

Huckabee so far has ignored calls from McCain supporters to quit the race and unite the party.

"To say that it is bad for the party for us to have a debate, that it is bad for the party for us to have an election? My gosh, I really would like to think that it is good for the party for us to talk about it," he said.

McCain says he is focused on winning enough delegates to secure the nomination and bring the party together.

"I respect Governor Huckabee and have always admired his principles and campaign. I have said that we have a lot of work to do to unite the party," he said.

After the mid-Atlantic primaries, the focus will turn to Wisconsin next Tuesday where both parties hold a primary, and Hawaii, which will hold a Democratic caucus.